Small airways, big challenge

Respiratory medicine has always been in a privileged position, because it has relatively easy access to its organ of interest. Chest radiographs have been one of the earliest widely adopted imaging techniques in medicine, whilst quantitative pulmonary function methods have generally been available for more than three quarters of a century. Add to this the sophisticated bronchoscopic inspection, sampling and intervention techniques, the modern molecular analysis of exhaled air and the direct topical administration of drugs: what else could one desire in terms of diagnosis, monitoring and therapy? Whilst cardiologists and nephrologists were struggling to obtain a close picture of their favourite organs in their patients, the pulmonologists had the luxury of having access to valuable information about pathology, physiology and cell function in lung disease. However, do we really know what is going on in the lung in health and disease? The lung is a complex, adaptive organ in terms of its anatomy [1], mechanics [1, 2], gas transport [1, 3] and cell biology [1, 4]. All these features turn out to be highly dynamic, balancing under delicate homeokinetic conditions …